Functional brown adipose tissue imaging technique

Abstract

Disclosed embodiments for assessing brown adipose tissue use imaging of metabolic contrast agents. For example, activated brown adipose tissue may be assessed by evaluating a difference in production of the hyperpolarized 13 C metabolic contrast agent from a pre-polarized 13 C metabolic contrast agent precursor before and after exposure of the subject to an activating event or agent. In one embodiment, the subject is given a dose of norepinephrine, and the production of the hyperpolarized 13 C metabolic contrast agent before and after the dose is assessed.

The invention claimed is:  
     
       1. A method for detecting brown adipose tissue, comprising:
 acquiring one or more images of an adipose tissue of a subject representative of a relative level of a pre-polarized metabolic contrast agent, its metabolic products, or a combination thereof; 
 acquiring one or more activated tissue images of the subject representative of a relative level of the pre-polarized metabolic contrast agent and/or its metabolic products after exposing the subject to a brown adipose tissue activating agent or event; 
 determining a difference between the one or more images and the one or more activated tissue images; and 
 determining a presence or volume of brown adipose tissue activation based at least in part on the difference between the one or more images and the one or more activated tissue images. 
 
     
     
       2. The method of  claim 1 , wherein the brown adipose tissue activating agent or event comprises administration of an adrenergic agonist. 
     
     
       3. The method of  claim 2 , wherein the adrenergic agonist comprises norepinephrine. 
     
     
       4. The method of  claim 1 , wherein the brown adipose tissue activating agent or event comprises a reduction in a core or skin temperature of the subject. 
     
     
       5. The method of  claim 1 , wherein the brown adipose tissue activating agent or event comprises a reduction in a skin temperature of the subject without a reduction of more than 1-2 degrees C. of core body temperature of the subject. 
     
     
       6. The method of  claim 1 , comprising identifying one or more locations of brown adipose tissue activation in the subject based on the difference. 
     
     
       7. The method of  claim 1 , wherein the one or more images and the activated tissue images are taken after the brown adipose tissue activating agent or event that comprises administration of an adrenergic agonist, a reduction in a core or skin temperature of the subject, or a combination thereof. 
     
     
       8. The method of  claim 1 , wherein the one or more are taken after the brown adipose tissue activating agent or event, wherein the brown adipose tissue activating agent or event that comprises administration of an adrenergic agonist, a reduction in a core or skin temperature of the subject, or a combination thereof. 
     
     
       9. The method of  claim 1 , wherein the one or more images comprise images of a cervical neck and supraclavicular region, chest, abdomen, or a combination thereof. 
     
     
       10. The method of  claim 1 , comprising acquiring one or more reference images before administration of the pre-polarized metabolic contrast agent. 
     
     
       11. The method of  claim 1 , wherein the pre-polarized metabolic contrast agent comprises pre-polarized [1 13 C] pyruvate. 
     
     
       12. The method of  claim 1 , wherein the metabolic products of the pre-polarized metabolic contrast agent comprise hyperpolarized  13 C-bicarbonate, [1- 13 C] lactate, or a combination thereof. 
     
     
       13. The method of  claim 1 , wherein the one or more images are magnetic resonance images. 
     
     
       14. An imaging system, comprising:
 a processor configured to receive and process image data, wherein in the processor is configured to:
 receive a baseline tissue image of a subject with a  13 C metabolic contrast agent in a bloodstream of the subject; 
 receive an activated tissue image of a subject with the  13 C metabolic contrast agent in the bloodstream of the subject after exposing the subject to a brown adipose tissue activating agent or event, wherein the baseline tissue image and the activated tissue image are representative of a concentration of one or more hyperpolarized  13 C products of the  13 C metabolic contrast agent; 
 determine a difference between the baseline tissue image and the activated tissue image; and 
 determine a level or presence of brown adipose tissue activation based at least in part on the difference; and 
 
 a display coupled to the processor and configured to provide an indication related to the level or presence of brown adipose tissue activation. 
 
     
     
       15. The system of  claim 14 , wherein the processor is configured to receive a reference tissue image of the subject without the  13 C metabolic contrast agent in the bloodstream of the subject. 
     
     
       16. The system of  claim 14 , wherein the baseline images and the activated tissue images are taken at different time points after exposing the subject to a brown adipose tissue activating agent or event. 
     
     
       17. An imaging method, comprising:
 injecting a pre-polarized  13 C metabolic contrast agent into a bloodstream of a subject; 
 exposing the subject to a brown adipose tissue activating agent or event; and 
 providing one or more inputs to an imaging system to instruct the imaging system to obtain a plurality of images of the subject, wherein the images comprise a baseline tissue image and an activated tissue of the subject, wherein the baseline image is obtained before exposing the subject to the brown adipose tissue activating agent or event and the activated tissue image is acquired after exposing the subject to the brown adipose tissue activating agent or event. 
 
     
     
       18. The method of  claim 17 , comprising providing an indication to the subject related to a presence or level of activated brown adipose tissue. 
     
     
       19. The method of  claim 17 , wherein the images are images representative of a hyperpolarized metabolic product of the pre-polarized 13C metabolic contrast agent.